Circuit breaker



Oct. 1, 1940. K4 BAUERSCHL-HDT CIRCUIT BREAKER Filed Jan. 2, 1940 Inventor Kuno Bauehschmidb, by

H's Attorney.

Patented Oct. 1, 1940 PATENT OFFICE CIRCUIT BBEAKER Kuno Bauerschmidt, Karishorst, Germany, asaig'nor to General Electric Company, a corporation of New York I Application January 2, 1940, Serial No. 312,109

. In Germany January-10, 1939' UNITED STATES 9 Claims.

The present invention relates to electric circuit breakers, and more particularly to improvements in circuit breakers oi the gas blast type.

It is an object of this invention to provide-an 6' improved construction in gas blast switches which X is characterized by its compact and rugged construction, ease of manuiacture and assembly and 15 Further objects and advantages will become apparent as the following description proceeds, reference being had to the accompanying drawing in which Fig. 1 is an eievational view in section of a circuit breaker embodying the invention;

20 Fig. 2 is an end elevational view oi! the breaker of Fig. 1; Fig. 3 is an elevational view partially in section oi a modification; Fig. 4 isan end elevational view of another modification of the breaker arrangement of Fig. 1; Fig. 5 is a secv tional view taken along the line 5-4 of Fig. 4; and Fig. 6 is a sectional view taken along th line 6-6 of Fig. 4. V

Referring to the drawing, I have shown my invention embodied in a three-pole circuit breaker the expulsion type comprising a plurality of circuit-interrupting units illustrated generally by numeral it. Each of the units is preferably of identical construction and comprises an arcconfining structure ll, preferably in the form of a cylindrical sleeve or tube of suitablegasemitting material. The fixed contact I 2 is mounted I at one end of the tube "and secured in position by a metal cap i3 which may conveniently form one terminal of the breaker. The cap is secured to the tube in any suitable manner, for example, by a screw-threaded connection (not shown). A movable contact red It is arranged to enter the open end of the tube Ii and engage the fixed breaker. The contact ll slides in a suitable sleeve contact II which is electrically connected.

contact I! in the closed circuit position of the 24 in any suitable manner.

is received in aligned openings formed in the walls of the chamber i1 and is provided intermediate its ends with passages is which communicate with the interior of the chamber l1 and provide for the escape of the highly heated and ionized gases which are formed within the tube ll during the circuit-interrupting operation of the breaker. In order effectively to cool the gases exhausted from the passage iii the chamber Il may to advantage be formed of material 10 having good heat transfer properties, such as metal. The use of a heat-dissipating section in the path of the gases before they are expanded is very efiective since the gases are at their highest temperature at this point. The use of a conducting chamber increases the insulation problems however and in breakers for certain applications it may be preferable to construct the chamber ll of insulating material. The passages I8 are positioned in the walls of the tube Ii at such a distance from the fixed contact that they are uncovered during opening movement of the movable contact ll after the separation of the fixed and movable contacts has proceeded far enough to ex- 85 ti guish a heavy current arc.

breaker in which the insulating plate It forms a support for the interrupting units of each pole and also forms header for the expansion chembers 20; 2|, and 22. The expansion chambers are-preferably made from tubes of insulating material which are mounted concentrically on the header l6 and each is arrangedto communicate individually with the open end of a chamber. I! connected to a diiierent one of the interrupting units. The expansion chambers are each provided with a muiiier 23 in accordance with the well-known practice. As illustrated in Fig. 1 of the drawing, the breaker assembly is supported by the inner expansion chamber 22 irom a suitable support 24 by means of a clamping ring 25 which may be secured to the tube 23 and support Each of the expansion chambers 20, 2|, and 22 are of a different length to provide for exhausting the heated gases from the structure at spaced points along its length.

In the operation of the breaker, an arc is drawn between the relatively movable contacts during their separating movement. The arc acts upon the walls of the tube i i to liberate arc-extinguishing gas which is dependent, among other things, upon the magnitude of the current being interrupted. When the current is large, the arc is interrupted when there is a relatively short separation oi the relatively movable contacts and the passages I! are arranged to exhaust these highly heated gases into the chamber I1 and from there to the expansion chamber associated therewith. When the current being interrupted is small the arc is not extinguished until a greater separation of the contacts has taken place but, in these cases, the gases are much less highly heated and may be safely exhausted to the atmosphere through the open end of the arc-confining tube II.

In Fig. 3 I have shown my invention embodied in a modified circuit breaker construction which is very similar. to that described in connection with Figs. 1 and 2. In the construction shown in Fig. 3 the outer expansion chamber 20 is made longer than the other" expansion chambers and is secured to a longitudinally extending conduit 20 which may be arranged to receive the exhaust gases from a plurality of circuit breaker units of a complete installation. This construction totally encloses the exhaust gases which may be exhausted from the end of the building in which the switches are housed so that the possibility of flame being emitted in the vicinity of the breaker structure under severe operatng conditions is eliminated. Using the larger expansion chamber as a support also provides a more rugged and durable structure.

The present invention is not limited to a construction in which all of the expansion chambers are concentrically arranged, and in Figs. 4, 5, and 8 I have illustrated a modified structure embodying certain features of my invention. In the modified construction the interrupting units are supported from a conduit 20 by the out er blast chamber 20 in the same manner as that described in connection with Fig. 3. The inner,

expansion chambers, however, are arranged side by side within the outer expansion chamber.

The constructions described above have numerous advantages from a, manufacturing and installation standpoint. The concentric arrangement of the expansion chambers, one of which forms a support for the circuit-interrupting units, provides a very compact assembly which requires a minimum amount of space for a breaker of given voltage and current rating and eliminates the supporting bushings normally required to mount the breaker. The chamber I! which surrounds the arc-confining tube Ii may be readily formed of metal with the present construction and when so formed is very effective to dissipate the heat carried by gases exhausted through the intermediate passage II when a high current are is interrupted. The construction also provides easy access to the parts of the switch which require frequent inspection and occasional renewal such as the contact members and the arc-confining tube H. 1

While the present invention is particularly useful in connection with gas expulsion-type interrupters, it will be apparent that many features thereof are applicable to other types of circuit interrupters, and I intend in the appended claims to cover all modifications falling within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent 0! the United States, is:

1. A circuit breaker comprising in combination a circuit-interrupting unit including a 1101- low arc-confining structure having an exhaust passage intermediate its ends and relatively movable contacts separable to draw an are within said structure, an expansion chamber having an exhaust opening, and means communicating with said expansion chamber and said exhaust passage for supporting said interrupting unit outside said expansion chamber and for conducting exhaust gases from said interrupting unit to said expansion chamber.

2. A circuit breaker comprising in combination a circuit interrupting unit including an elongated hollow arc-confining structure having an exhaust passage in a side wall thereof and relatively movable contacts separable to draw an are within said structure, a support, an expansion chamber secured on said support, and means forming a conduit communicating with said exhaust passage and said expansion chamber for supporting said circuit-interrupting unit outside of said expansion chamber.

3. A circuit breaker comprising in combination a circuit-interrupting unit including an elongated hollow arc-confining structure having an exhaust passage in a side wall thereof and relatively movable contacts separable to draw an are within said structure, a support, a tubular expansion chamber secured on said support, a hollow member having an opening in a wall thereof communicating with said expansion chamber, said hollow member also having aligned openings in the spaced walls thereof in which said elongated arc-confining structure is received whereby said interrupting unit is supported outside of said expansion chamber and the gases exhaust from said intermediate exhaust passage are conducted to said expansion chamber.

4. A multipole circuit breaker comprising in combination a plurality of circuit-interrupting units each including an arc-confining structure and relatively movable contacts separable to draw an are within said structure, a plurality of expansion chambers mounted one within the other, and means for supporting said circuitinterrupting units in insulated relation on the outside of said expansion chambers and for conducting exhaust gases from the arc-confining structure of each of said interrupting units to a different one of said expansion chambers.

5. A multiple circuit breaker comprising in combination a plurality of circuit-interrupting units each including an arc-confining structure and relatively movable contacts separable to draw an are within said structure, a plurality of concentrically mounted expansion chambers, and means for supporting said circuit-interrupting units in insulated relation on the outside of said expansion chambers, and means for conducting exhaust gases from the arc-confining structure of each or said interrupting units to a diii'erent one 01 said expansion chambers.

6. A multiple circuit breaker comprising in combination a plurality of circuit-interrupting units each including a hollow arc-confining structure having an exhaust passage intermediate its ends and relatively movable contacts separable to draw an are within said structure, a plurality of expansion chambers mounted in concentric relation and each having an. exhaust opening, a plurality of intermediate chambers each having an opening communicating with a different one of said expansion chambers, each of said intermediate chambers being constructed 78 and arranged to support oneoi said interrupting units outside of said expansion chambers and to conduct exhaust gases from the exhaust passage thereor'to one of said expansion chambers.

7. A multipole circuit breaker comprising in combination a plurality of circuit-interrupting units each including an arc-confining structure and relatively movable contacts separable to draw an are within said structure, a supporting member, a plurality of expansion chambers of varying lengths secured together and mounted one within the other, the longer of said expansion chambers being connected to and supported by said member, and means for supporting each of said circuit-interrupting units outside of said expansion chambers and for conducting exhaust gases from the arc-confining structure of each of said interrupting units to a diiferent one of said expansion chambers.

8. A circuit breaker comprising in combination,'a support, a plurality of concentrically arranged expansion chambers on said support, a header closing one end of said expansion chambers, a plurality of circuit-interrupting units each including a hollow arc-confining structure having an exhaustpassage intermediate its ends and relatively movable contacts separable to draw an are within said structure, a plurality said expansion chambers and to conduct ex-' haust gases from the intermediate exhaust passage thereof to one of said expansion chambers.

9. A multipole circuit breaker comprising a plurality of expansion chambers, means for mounting said chambers in. concentric relation,

a plurality of circuit-interrupting units mounted outside of said expansion chambers, and means for conducting exhaust gases from each of said circuit-interrupting units to a different one of said expansion chambers.

KUNO ABAUERSCHM'IUI. 

